Brussels threatened to trigger moves soon aimed at halting Poland's voting rights in the 28-nation bloc due to a "grave" threat to Polish judicial independence.

It also warned it could launch other disciplinary action as early as next week.

Thousands of protesters have taken to the streets in Polish cities against the governing Law and Justice party's reforms, which would give parliament powers over the selection of judges.

"These laws considerably increase the systemic threat to the rule of law in Poland," European Commission vice president Frans Timmermans said after a high-level meeting on Poland.

"Collectively, they would abolish any remaining judicial independence and put the judiciary under full political control of the government."

The Dutchman added that "we are very close to triggering article seven" -- the bloc's never-before used "nuclear option" that can halt a country's right to vote in EU meetings.

Poland would, however, likely escape such a measure as it would be vetoed by its ally Hungary.

The clash underscores a growing rift between Brussels and many eastern member states, where populist and increasingly authoritarian governments are pushing for greater sovereignty, particularly over migration.

The EU first warned Poland in early 2016 over reforms of the constitutional court by the Law and Justice party, which won elections in late 2015.

The European Commission said in a statement that it "urges the Polish authorities to put the new laws on hold" and to re-engage in dialogue.

It said it would "swiftly prepare infringement procedures for breach of EU law" to possibly be launched against Warsaw next week at another high-level Commission meeting.

EU states can be taken to the bloc's highest court and eventually given stiff fines for such breaches.

Separately, Brussels gave the latest in a series of hints that Poland could receive less in EU funding if it does not comply.

The latest of the Polish reforms -- a draft law giving the justice minister power to make appointments to the supreme court -- triggered angry exchanges in the Polish parliament late Tuesday.

Law and Justice party chief Jaroslaw Kaczynski said opponents "murdered" his brother Lech Kaczynski, the then-president of Poland who was killed in a jet crash in Russia in 2010.

Thousands of Poles protested judicial reform plans

On Sunday, thousands rallied in Warsaw and other cities against reforms endorsed last week by parliament and more protests took place Tuesday in Warsaw.

The first of those laws stipulates that from now on the parliament will choose the members of the National Council of the Judiciary, which oversees the selection of judges and is meant to protect the independence of the courts. The second bill states that the justice minister will name the chief justices of Poland's common courts.

Both texts need only to be signed by President Andrzej Duda, who is closely allied with the Law and Justice party, to become law.

But Duda, in a surprise move on Tuesday, warned he would not approve the supreme court reform unless lawmakers amended the bill on the judiciary council to ensure that the Law and Justice Party would not have complete control over its composition.

Relations between Warsaw and Brussels have deteriorated in recent months, with Poland making a failed bid to scupper the re-election of European Council president Donald Tusk, a former Polish premier and bitter foe of the Kaczynskis.

Brussels has stepped up the pressure on several eastern members by taking legal action against Hungary, Poland and the Czech Republic over a series of issues in recent weeks.

Media freedom also under threat

The European Union called Wednesday for an end to the "intimidation" of journalists critical of Poland's right-wing government, saying that media freedom should be respected.

European Commission vice president Frans Timmermans spoke out following reports that a Polish reporter based in Brussels was threatened on social media after Polish state TV accused her of trying to "harm" the country.

"I would call upon everyone involved in this discussion, to stop it already with this intimidation of journalists if they feel that journalists are asking too critical questions," Timmermans told a news conference in Brussels.

"What should not be happening is that journalists are intimidated to do their work," he added.

The Dutch former foreign minister added: "'In darkness democracy dies', I think is the motto of the Washington Post. For democracy we need the press to be able to work unimpeded, free."

A Brussels-based journalists' group, the International Press Association (IPA), has raised concerns over the treatment of Dorota Bawolek, a correspondent for Polsat, a private and independent television channel.

Bawolek has been the target of hundreds of insulting and threatening messages on social media, after state-controlled Polish TV said she asked the European Commission politically motivated questions with intent "to harm Poland", the Euractiv website reported.

Timmermans said earlier this week on Twitter: "I strongly condemn the threats @DorotaBawolek received just for doing her job. Unacceptable! Un-EU!"

The IPA said it welcomed the EU appeal but urged the Commission to "assertively" uphold the right to freedom of expression.

Poland's governing Law and Justice party has been accused by media and rights groups of seeking to limit press freedoms, including by ramping up state control over public broadcasters and restricting journalists' rights to cover parliament.